A variety of different applications use motion sensors to detect the motion of an underlying object. One widely used application involves detecting the motion of an automobile. Specifically, motion sensors often are mounted about the periphery of an automobile chassis to sense pre-specified accelerations or rotations. Those in the art typically refer to such sensors as “satellite sensors.”
When a satellite sensor detects a pre-specified type of motion, systems within the automobile respond in an pre-specified manner. For example, if a satellite sensor detects a sudden and high deceleration, air-bag systems may deploy their air bags. Alternatively, if a satellite sensor detects a sudden rotation (e.g., the automobile is swerving), breaking systems may selectively break to avoid a rollover. Accordingly, satellite sensors have become critical in ensuring automobile safety.
Currently available satellite sensors typically have a relatively large housing that contains both a printed circuit board with electronics for detecting motion, and a mounting device (e.g., bushings) for mounting the housing to the automobile. Moreover, to facilitate mounting, the housing generally is molded to a shape that conforms to the specific geometry of the portion of the chassis to which it is to be mounted. Use of such a satellite sensor, however, is undesirable for a number of reasons. Among other things, its use of a printed circuit board with a relatively high number of electronic components necessitates the relatively large housing. This runs counter to the trend toward miniaturizing electronics.
In addition, although desirable in some instances, many currently available satellite sensors can be mounted to their underlying automobile chassis in only one orientation. For example, a satellite sensor may have two substantially parallel spaced bushings for receiving screws that couple with corresponding holes in the automobile chassis. The sense axis of such a satellite sensor thus can be oriented relative to no more than one axis of the automobile. Accordingly, the bushings must be positioned in a pre-specified location of the housing so that, when mounted to the chassis, the sense axis is aligned with the appropriate axis of the automobile. If not, then another satellite sensor with a different bushing configuration must be used. In other words, if a first satellite sensor is not configured to orient its sense axis along a desired axis, then another satellite sensor with bushings that orient the sense axis in a different direction (i.e., the direction of interest) must be used.